The present disclosure relates to a coil component, and more particularly, to a coil component used as a noise filter.
In accordance with the development of consumer electronics, electronic devices such as portable phones, home appliances, personal computers (PCs), personal digital assistants (PDAs), liquid crystal displays (LCDs), and the like, have changed from using an analog scheme to a digital scheme, while the speed of electronic devices has been increased, due to increasing amounts of data required to be processed by electronic devices.
Therefore, universal serial bus (USB) 2.0, USB 3.0, and high-definition multimedia interface (HDMI) standards have been widely used in high speed signal transmitting interfaces, and have been used in many digital devices such as personal computers and digital high-definition televisions.
In such high speed interfaces, a differential signal system, in which differential signals (differential mode signals) are transmitted using a pair of signal lines, is adopted, unlike a single-end transmitting system that has generally been used for a long period of time. However, electronic devices that are digitized and have increased speeds are sensitive to external stimuli, such that distortion of signals due to high frequency noise is a common occurrence.
In order to remove such noise, a filter has been installed in electronic devices. Particularly, a common mode filter, a coil component for removing common mode noise, has been widely used in high speed differential signal lines, or the like.
Common mode noise is noise generated in differential signal lines, and common mode filters remove common mode noise that may not be removed by existing filters.
Meanwhile, as frequencies used in electronic products have gradually been increased, common mode filters having improved narrowband characteristics and attenuation characteristics in a high frequency band have been required. For instance, narrowband characteristics of about ±25% to ±20%, based on common mode impedance of 90Ω, high attenuation characteristics of −30 dB or more in a band of several GHz, and the like have been required.
Thus, in order to significantly reduce magnetic loss, a common mode filter having a structure in which a coil layer is directly exposed to air without a separate magnetic member such as a ferrite-resin composition layer has been suggested.
However, in this case, during a process of soldering mounting components, a problem in which mountability is deteriorated, for example, occurrence of a short circuit between electrodes, or the like, may occur.
In addition, deviations in a coefficient of thermal expansion between members forming the common mode filter, for example, a magnetic substrate and an insulating layer in contact with the magnetic substrate may be severe. As a result, defects such as warpage, or the like, may occur in the product itself.